The parotid gland will be used as a model system for studies on the regulation of secretory processes as well as a model for studies on the mechanism of action of neuro-hormones (i.e. beta-adrenergic, alpha-adrenergic and cholinergic agonists). In the current context the role of Ca ion 2, cyclic AMP, and cyclic GMP in the interaction of cholinergic, alpha-adrenergic and beta-adrenergic agonists on alpha-amylase release and K ion efflux will be explored. These studies will entail characterization of the enzymes which degrade the cyclic nucleotides, of the receptor moieties for the cyclic nucleotides and of the cyclic nucleotide dependent protein kinase activities in the parotid. The possibility of modulating the activities of these enzymes by agonists and Ca ion 2 will be investigated. The effect of the various agonists, Ca ion 2 and exogenous cyclic nucleotides on the phosphorylation of parotid proteins will also be investigated. Experiments will be conducted to identify the intracellular altered levels of phosphorylation of these substrates with altered physiological function.